This application is based on Application No. 2000-208766, filed in Japan on Jul. 10, 2000, the contents of which are hereby incorporated by reference.
This invention relates to a coil conductor for an electrical apparatus and particularly to a coil conductor for dynamoelectric machine suitable for use as a coil conductor to be inserted into slots of a dynamoelectric machine such as an electric motor and a generator.
FIG. 30 illustrates a coil conductor for a dynamoelectric machine as one example of a conventional coil conductor 101 for an electrical apparatus, which is made of a copper sheet material and has straight portions 102 to be inserted into iron core slots and crossover portions 103 connected to the end portions of the straight portions 102.
Since the conventional sheet-shaped coil conductor 101 of the dynamoelectric machine are made of a copper sheet as shown in FIG. 30, a phenomenon known as a skin effect occurs in which a deviation of current density within the conductor is generated due to the difference in inductance about the coil at a higher dynamoelectric machine frequency, so that an electric current flowing through the conductor is decreased to lower the output for the same line voltage. In order to compensate the resistance increase due to the skin effect, the position of the conductor series connected in one phase must be changed within each slot, the provision of a measure such as the braiding of the conductor is necessary, decreasing the productivity.
Also, when a multiplex winding is desired, as shown in FIG. 31, a first and a second parallel circuit 43 and 46 are first formed and, during the winding of the winding 40, an electrical connection must be established between an inner-layer winding 41 and an outer-layer winding 42 as well as between an inner-layer winding 44 and an outer-layer winding 45, resulting in the increased cost due to the decreased productivity and increased number of connection portions. Also, since the conductor has a shape cranked in a serpentine manner, redundant material is generated when cut out from a blank copper plate, degrading the yield and necessitating forming such as bending, cutting or the like, whereby the productivity is low.
Accordingly, an object of the present invention is to provide a coil conductor for a dynamoelectric machine that is small in skin effect even with a high dynamoelectric machine frequency and maintaining an output.
Another object of the present invention is to provide a coil conductor for a dynamoelectric machine that is simple in coil conductor arrangement and improved in the productivity.
Another object of the present invention is to provide a coil conductor for a dynamoelectric machine in which the electrical connection can be easily made even when the multiplex winding is used, thus preventing the cost increase.
Still another object of the present invention is to provide a coil conductor for a dynamoelectric machine in which the yield of the conductor material is not decreased and working such as bending or cutting can be made unnecessary to improve the productivity.
With the above objects in view, the present invention resides in a coil conductor for a dynamoelectric machine which is a coil conductor to be inserted into slots of an iron core of a dynamoelectric machine, said coil conductor being made of a plurality of wire elements compression-bonded to each other by press-forming so as to have a substantially rectangular cross-section.
The wire elements may be twisted by at least 360 degrees.
The wire elements, which are made of a plurality of strands twisted by at least 360 degrees, may be twisted.
The coil conductor may comprise straight sections to be inserted into said slots of said iron core and crossover sections connected between said straight sections and axially projecting from opposite end portions of said iron core, providing an overall shape of a crank wound in a serpentine manner.
The straight sections may have different intervals therebetween that are different in accordance with the different periodical numbers n th and (n+1) th and said straight sections are assembled into said slots.
The straight section and said crossover section may have substantially equal cross-sectional area, and said straight section has a thickness dimension that is greater than a thickness dimension of said crossover section.
The coil conductor for a dynamoelectric machine may further comprises an electrical insulating material disposed around the conductor of a square cross-sectional shape that is formed by simultaneously pressing the conductor bundle with an electrical insulating material placed therearound before press-forming.
The electrical insulation may be provided around the conductor of a square conductor.
The plurality of square conductors may be simultaneously provided by press-forming a plurality of bundled or braided conductors.
The coil conductor may be a multi-phase winding conductor for a multi-phase a.c. current.
The coil conductor may be arranged such that wire connection ends at equal electric potential are connected prior to the press-forming and successively press-formed into a flat square bar.
The coil conductor may be arranged such that a bundle of a plurality of conductor elements are press-formed while being braided and repeating the press-forming to provide the coil.
The wire elements may be made of magnet wire.
The wire elements may be bare wires.
The wire elements may be bare wires with an oxide skin thereon.
The wire elements may be made of magnet wires and wherein said coil conductor is made by press-forming a twisted bundle of magnet wires coated with an insulating material, from which the insulating coatings are removed from portions that become connection points when wound into the coil winding.
The winding may have one end connected to the portion from which the insulating coating is removed after the press-forming and the other end connected to the portion from which the insulating coating is removed before or after the press-forming.
The coil conductor may be a three-phase conductor of which U-phase conductor is made longer than V- and W-phase conductors and wherein a common connection points are connected using said longer U-phase conductor as a shunt.
An electrically insulating coating may be provided on the lead wire portion to prevent short-circuiting at the lead wire portion.
A portion of the conductor that is not yet press-formed may be used as a lead wire.